otherwise GCLK_AC is disabled until the next edge detection. Filtering is not possible with this
configuration.
Figure 42-9. Continuous Mode SleepWalking
GCLK_AC
STATUSB.READYx
Sampled
Comparator Output
COMPCTRLx.ENABLE
t
STARTUP
Write ‘1’
2-3 cycles
42.6.14.2. Single-Shot Measurement during Sleep
For low-power operation, event-triggered measurements can be performed during sleep modes. When
the event occurs, the Power Manager will start GCLK_AC. The comparator is enabled, and after the start-
up time has passed, a comparison is done, with filtering if desired, and the appropriate peripheral events
and interrupts are also generated, as shown in
. The comparator and GCLK_AC are then
disabled again automatically, unless configured to wake the system from sleep. Filtering is allowed with
this configuration.
Figure 42-10. Single-Shot SleepWalking
GCLK_AC
Comparator
Output or Event
Input Event
t
STARTUP
t
STARTUP
42.6.15. Synchronization
Due to asynchronicity between the main clock domain and the peripheral clock domains, some registers
need to be synchronized when written or read.
The following bits are synchronized when written:
•
Software Reset bit in control register (CTRLA.SWRST)
•
Enable bit in control register (CTRLA.ENABLE)
•
Enable bit in Comparator Control register (COMPCTRLn.ENABLE)
The following registers are synchronized when written:
•
Window Control register (WINCTRL)
Required write-synchronization is denoted by the "Write-Synchronized" property in the register
description.
Related Links
Atmel SAM L22G / L22J / L22N [DATASHEET]
Atmel-42402E-SAM L22G / L22J / L22N_Datasheet_Complete-07/2016
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